Heat pump system for vehicle

ABSTRACT

A heat pump system for a vehicle may include an outdoor condenser, an expansion valve, an evaporator, a compressor, and an indoor condenser that primarily condenses the refrigerant compressed through the compressor and is connected with the outdoor condenser, in which the outdoor condenser, the expansion valve, the evaporator, the compressor, and the indoor condenser are connected through refrigerant pipes, a first valve disposed in the refrigerant pipe between the outdoor condenser and the expansion valve; a chiller connected with the first valve through the refrigerant pipe, between the evaporator and the compressor, and controls the temperature of the refrigerant by exchanging heat; a connection pipe selectively allowing some of the refrigerant flowing into the chiller in a dehumidifying mode; and a second valve disposed in the connection pipe.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2013-0148737 filed on Dec. 2, 2013, the entire contents of which application are incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a heat pump system for a vehicle. More particularly, the present invention relates to a heat pump system for a vehicle which increases the travel distance of a vehicle by reducing the use of a PTC heater and of which the entire efficiency is improved, by being able to continuously run a dehumidifying mode with a heating mode for heating the vehicle, if necessary, when working in the heating mode in winter.

2. Description of Related Art

In general, automotive air-conditioning systems include an air-conditioning module for heating/cooling the interior of vehicles.

Such air-conditioning modules are designed to cool the interior of vehicles, using a heat exchange medium, which is discharged from a compressor and exchanges heat through an evaporator while circulating through a condenser, a receiver drier, an expansion valve, the evaporator, and the compressor, or they heat the interior of vehicles, using cooling water that exchanges heat through a heater.

Recently, there is a need of developing an environmentally-friendly vehicle that can substantially replace the ICE (Internal Combustion Engine) vehicles, with an increasing concern on energy efficiency and the problem with environmental pollution and the environmentally-friendly vehicle generally falls into an electric vehicle driven by a fuel cell or electricity, which is the power source, and a hybrid vehicle driven by an engine and an electric battery.

In those environmentally-friendly vehicles, the electric vehicles are not equipped with a specific heater, unlike the air-conditioning systems of common vehicles, and the air-conditioning systems used for the electric vehicles are usually called heat pump systems.

In the heat pump systems, the way of decreasing the temperature and humidity of the interior of vehicles in a cooling mode in summer by condensing high-temperature and high-pressure gaseous refrigerant, which has been compressed by a compressor, through a condenser and evaporating it through a receiver drier and an expansion valve, is the same as the way of common air-conditioning system; however, the high-temperature and high-pressure gaseous refrigerant is used as a heating medium in a heating mode in winter.

That is, in the heating mode of electric vehicles, the high-temperature and high-pressure gaseous refrigerant flows into not the outdoor condenser, but the indoor condenser through a valve and exchanges heat with external air sucked therein and the external air with heat exchanged flows into the interior of the vehicles through a PCT (Positive Temperature Coefficient) heater, such that the temperature of the interior of the vehicles increases.

The high-temperature and high-pressure gaseous refrigerant flowing in the indoor condenser is discharged as a liquid refrigerant after condensing by exchanging with the external air therein.

However, the heat pump systems of the related art described above have to stop operating in the heating mode, change into a heating mode using the PTC heater, and then change into the cooling mode, when dehumidification is required while they operate in the heating mode in winter, such that noise is generated and durability is reduced by frequent changes between the heating mode and the cooling mode and the performance of the entire heat pump systems is deteriorated.

Further, when the dehumidifying mode is frequently operated, the power consumption increases due to expansion of the use range of the PTC heater, so the whole travel distance by the same power reduces.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a heat pump system for a vehicle having advantages of being able to prevent noise and a decrease in durability due to frequent changes between a heating mode and a cooling mode in the related art, and improve the efficiency of the entire system by increasing the travel distance of a vehicle with reduction of the use of a PTC, by performing a heating mode and a dehumidifying mode even without changing into a cooling mode, when interior dehumidification is required during the heating mode in winter.

In an aspect of the present invention, a heat pump system for an electric vehicle which controls cooling/heating of an interior of the electric vehicle by circulating a refrigerant in accordance a heating mode and a cooling mode, may include an outdoor condenser that condenses the refrigerant, an expansion valve that is fluidly-connected to the outdoor condenser and expands the refrigerant condensing through the outdoor condenser, an evaporator that is fluidly-connected to the expansion valve and evaporates the refrigerant expanding through the expansion valve, a compressor that is fluidly-connected to the evaporator and compresses the refrigerant evaporating through the evaporator, an indoor condenser that primarily condenses the refrigerant compressed through the compressor, wherein the indoor condenser is connected with the outdoor condenser, the expansion valve, the evaporator, the compressor, and the indoor condenser through refrigerant pipes, a first valve disposed in a first refrigerant pipe of the refrigerant pipes between the outdoor condenser and the expansion valve, a chiller connected with the first valve through a second refrigerant pipe, between the evaporator and the compressor, and controls a temperature of the refrigerant by exchanging heat, a connection pipe selectively allowing some of the refrigerant flowing into the chiller in a dehumidifying mode, and a second valve disposed in the connection pipe.

The connection pipe connects the second refrigerant pipe disposed between the first valve and the chiller with a third refrigerant pipe disposed between the expansion valve and the evaporator.

The chiller is connected with an accumulator disposed between the evaporator and the compressor, through the third refrigerant pipe, wherein the third refrigerant pipe connects the evaporator, the accumulator, the compressor, and the indoor condenser.

The second valve is a check valve that prevents the refrigerant from flowing back into the chiller from the evaporator through the connection pipe.

The first valve is a 3-Way valve.

A fourth refrigerant pipe of the refrigerant pipes may further have an orifice between the outdoor condenser and the indoor condenser, wherein the fourth refrigerant pipe connects the outdoor condenser and the indoor condenser.

In the heating mode, the refrigerant from the outdoor condenser is sent not into the expansion valve and the evaporator, but into the chiller by an operation of the first valve, and is then sent, with the temperature increased, into the compressor, and when the dehumidifying mode is required during the heating mode, some of the refrigerant flowing into the chiller is sent into the evaporator through the connection pipe by opening the second valve, with the heating mode keeping operated.

In another aspect of the present invention, a heat pump system for an electric vehicle which controls cooling/heating of an interior of the electric vehicle in accordance with a heating mode and a cooling mode, may include an outdoor condenser that condenses a refrigerant, an expansion valve that is fluidly connected to the outdoor condenser and expands the refrigerant condensing through the outdoor condenser, an evaporator that is fluidly connected to the expansion valve and evaporates the refrigerant expanding through the expansion valve, a compressor that that is fluidly connected to the evaporator and compresses the refrigerant evaporating through the evaporator, an indoor condenser that primarily condenses the refrigerant compressed through the compressor, wherein the indoor condenser is connected with the outdoor condenser, the expansion valve, the evaporator, the compressor, and the indoor condenser, through refrigerant pipes, a first valve disposed in a first refrigerant pipe of the refrigerant pipes between the outdoor condenser and the expansion valve, a chiller connected with an accumulator between the evaporator and the compressor, disposed between the first valve and the accumulator, and controlling a temperature of the refrigerant by exchanging heat, a connection pipe connected to a second refrigerant pipe of the refrigerant pipes disposed between the expansion valve and the evaporator, to a third refrigerant pipe of the refrigerant pipes disposed between the outdoor condenser and the indoor condenser to selectively send some of the refrigerant flowing into the outdoor condenser to the evaporator in the dehumidifying mode, and a second valve disposed in the connection pipe.

The second valve is a check valve that prevents the refrigerant in the connection pipe from flowing back into the chiller from the evaporator.

The first valve is a 3-Way valve.

The third refrigerant pipe may include an orifice between the outdoor condenser and the indoor condenser and the connection pipe is connected with the third refrigerant pipe between the orifice and the outdoor condenser.

In the heating mode, the refrigerant from the outdoor condenser is sent not into the expansion valve and the evaporator, but into the chiller by an operation of the first valve, and is then sent, with the temperature increased, into the compressor, and when the dehumidifying mode is required during the heating mode, some of the refrigerant flowing into the chiller is sent into the evaporator through the connection pipe by opening the second valve, with the heating mode keeping operated.

As described above, according to a heat pump system for a vehicle of an exemplary embodiment of the present invention, it is possible to prevent noise and a decrease in durability due to frequent changes between a heating mode and a cooling mode in the related art, and improve the efficiency of the entire system by increasing the travel distance of a vehicle with reduction of the use of a PTC, by performing a heating mode and a dehumidifying mode even without changing into a cooling mode, when interior dehumidification is required during the heating mode in winter.

Further, in the dehumidifying mode, it is possible to reduce the manufacturing cost by decreasing the lengths of the connection pipes for supplying a refrigerant to the evaporator to simplify the layout inside a small engine room, such that it is possible to improve spatial usability and reduce a loss of internal pressure by simplifying the package.

Further, since it is possible to prevent unnecessary power consumption by reducing the use of a PTC heater and improving the efficiency of the entire system, it is possible to increase the travel distance with the same amount of power.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the configuration of a heat pump system for a vehicle according to an exemplary embodiment of the present invention.

FIG. 2 is a diagram illustrating a dehumidifying mode in a heating mode of the heat pump system for a vehicle according to an exemplary embodiment of the present invention.

FIG. 3 is a block diagram illustrating the configuration of a heat pump system for a vehicle according to another exemplary embodiment of the present invention.

FIG. 4 is a diagram illustrating a dehumidifying mode in a heating mode of the heat pump system for a vehicle according to another exemplary embodiment of the present invention.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTIONS

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

First of all, the exemplary embodiments described herein and the configurations shown in the drawings are the most preferable exemplary embodiments of the present invention and do not fully cover the spirit of the present invention, therefore, it should be understood that there may be various equivalents and modifications that can replace them at the time of the application.

Throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

Further, the terms, “. . . unit”, “. . . mechanism”, “. . . portion”, “. . . member” etc. used herein mean the units of inclusive components performing at least one or more functions or operations.

FIG. 1 is a block diagram illustrating the configuration of a heat pump system for a vehicle according to an exemplary embodiment of the present invention and FIG. 2 is a diagram illustrating a dehumidifying mode in a heating mode of the heat pump system for a vehicle according to an exemplary embodiment of the present invention.

Referring to the figures, a heat pump system 10 for a vehicle according to an exemplary embodiment of the present invention, which is used in electric vehicles, can prevent noise and a decrease in durability due to frequent changes between a heating mode and a cooling mode in the related art, and improve the efficiency of the entire system by increasing the travel distance of a vehicle with reduction of the use of a PTC, by performing a heating mode and a dehumidifying mode even without changing into a cooling mode, when interior dehumidification is required during the heating mode in winter.

To this end, the heat pump system 10 for a vehicle according to an exemplary embodiment of the present invention, as shown in FIG. 1, includes an outdoor condenser 13, an expansion valve 15, an evaporator 17, a compressor 19, and an indoor condenser 21 that are connected through refrigerant pipes 11 to control heating/cooling of the interior of a vehicle, using circulation of a refrigerant, depending on a heating mode and a cooling mode in an electric vehicle.

The outdoor condenser 13 is disposed ahead of a radiator ahead of an engine room, and condenses a refrigerant, using heat exchange with external air, and the expansion valve 15 expands the refrigerant condensing through the indoor condenser 13.

The evaporator 17 evaporates the refrigerant expanding through the expansion valve 15, the compressor 19 compresses the refrigerant evaporating through the evaporator 17, and the indoor condenser 21 is connected with the outdoor condenser 13 and primarily condenses the refrigerant compressed through the compressor 19.

The heat pump system 10 for a vehicle according to an exemplary embodiment of the present invention further includes a first valve 27, a chiller 29, connection pipe 31, and a second valve 33.

The first valve 27 is disposed in the refrigerant pipe 11 between the outdoor condenser 13 and the expansion valve 15.

The chiller 29, which is a water-cooled using cooling water as a cooling medium, is connected with the first valve 27 through the refrigerant pipe 11, between the evaporator 17 and the compressor 19 and controls the temperature of the refrigerant by exchanging heat with the cooling water with the temperature increased by cooling electric devices.

The second valve 27 may be a 3-way valve, and accordingly, it passes the refrigerant, which has condensed through the outdoor condenser 13, into the chiller 29, or into the expansion valve 15, not through the chiller 29.

Further, the chiller 29 may be disposed between the evaporator 17 and the compressor 19 and connected with an accumulator 23, which supplies only a gaseous refrigerant to the compressor 19, through the refrigerant pipe 11.

Accordingly, the accumulator 23 separates a liquid refrigerant in the refrigerant passing through the chiller 29 and in the gaseous refrigerant flowing into the compressor 19 through the evaporator 17, supplies the gaseous refrigerant to the compressor 19, and keeps the liquid refrigerant and then vaporizes and supplies it back to the compressor 19, such that it supplies only a gaseous refrigerant to the compressor 19. Therefore, breakdown and malfunction of the compressor 19 are prevented and efficiency and durability are improved.

In the present exemplary embodiment, the refrigerant pipe 11 may further include an orifice 25 between the outdoor condenser 13 and the indoor condenser 21.

In the present exemplary embodiment, the connection pipe 31 selectively allows some of the refrigerant, which flows into the chiller 29 by the operation of the first valve 27, into the evaporator 17 in a dehumidifying mode, and the second valve 33 is disposed in the connection pipe 31.

The connection pipe 31 connects the refrigerant pipe 11 between the first valve 27 and the chiller 29 with the refrigerant pipe 11 between the expansion valve 15 and the evaporator 17.

The second valve 33 may be a check valve that prevents backflow of fluid for preventing the refrigerant from flowing back into the chiller 29 from the evaporator 17 through the connection pipe 31.

The operation and effect of the dehumidifying mode when the heat pump system 100 for a vehicle which has the configuration described above, according to an exemplary embodiment of the present invention, are described in detail hereafter.

First, in the heating mode for winter in an electric vehicle equipped with the heat pump system 10 having the configuration described above, as shown in FIG. 2, cooling water with the temperature increased due to waste heat sources by cooling electric devices flows into the chiller 29 and is then cooled by exchanging heat with external air through a radiator and supplied back to the electric devices, thereby circulating.

In this process, the first valve 27 keeps opening the refrigerant pipe 11 connected with the chiller 29 so that the low-temperature condensed refrigerant from the outdoor condenser 13 is supplied to the chiller 29, and keeps closing the refrigerant pipe 11 connected with the expansion valve 15.

Accordingly, the refrigerant is condensed at lower temperature and low pressure by exchanging heat with the external air through the outdoor condenser 13 and then flows into the chiller 29 through the refrigerant pipe 11 connected with the chiller 29.

The refrigerant flowing in the chiller 29 flows, with the temperature increased by exchanging heat with the cooling water of which the temperature increased, into the compressor 19 through the accumulator 23, and the compressor 19 compresses the refrigerant with the temperature increased into a high-temperature and high-pressure gaseous refrigerant and supplies it to the indoor condenser 21.

The indoor condenser 21 is disposed in an HVAC (Heating, Ventilation and Air Conditioning) module and the external air is increased in temperature through the indoor condenser 21, such that warm external air is supplied to the interior of a vehicle by selective operation of the PTC heater, and thus, heating is made.

Thereafter, the refrigerant, which discharged heat by exchanging heat with the external air flowing into the interior while passing through the indoor condenser 21, changes into a low-temperature and low-pressure refrigerant through the orifice 25, and then it is condensed by exchanging heat with external air through the outdoor condenser 13 and supplied back to the chiller 29. Accordingly, the vehicle is heated by repeating the processes described above.

When there is a need of a dehumidifying mode due to moisture produced on the windows inside the vehicle during the heating mode, some of the refrigerant to flow into the chiller 29 through the connection pipe 31 is sent into the evaporator 17 by opening the second valve 33, with the heating mode keeping operated.

Accordingly, the external air flowing in the HVAC module is sent directly to the windows inside the vehicle, with the temperature decreased through the evaporator 17 with the low-temperature and low-pressure refrigerant therein, before it is supplied to the chiller 29, such that it removes the moisture.

Accordingly, since the heat pump system 10 for a vehicle according to an exemplary embodiment of the present invention can perform the dehumidifying mode during the heating mode, even without changing into a cooling mode after stopping a heating mode, as in the related art, when it is required to operate in the dehumidifying mode during the heating mode in winter, it is possible to prevent noise and reduction of the durability of the entire system due to frequent changes between a heating mode and a cooling mode.

FIG. 3 is a block diagram illustrating the configuration of a heat pump system for a vehicle according to another exemplary embodiment of the present invention and FIG. 4 is a diagram illustrating a dehumidifying mode in a heating mode of the heat pump system for a vehicle according to another exemplary embodiment of the present invention.

Referring to FIG. 3, the heat pump system 100 for a vehicle according to another exemplary embodiment of the present invention, as shown in FIG. 1, includes an outdoor condenser 113, an expansion valve 115, an evaporator 117, a compressor 119, and an indoor condenser 121 that are connected through refrigerant pipes 111 to control heating/cooling of the interior of a vehicle, using circulation of a refrigerant, depending on a heating mode and a cooling mode in an electric vehicle.

The indoor condenser 113 is disposed ahead of a radiator ahead of an engine room, and condenses a refrigerant, using heat exchange with external air, and the expansion valve 115 expands the refrigerant condensing through the indoor condenser 113.

The evaporator 117 evaporates the refrigerant expanding through the expansion valve 115, the compressor 119 compresses the refrigerant evaporating through the evaporator 117, and the indoor condenser 121 is connected with the outdoor condenser 113 and primarily condenses the refrigerant compressed through the compressor 119.

The heat pump system 100 for a vehicle according to another exemplary embodiment of the present invention further includes a first valve 127, a chiller 129, connection pipe 131, and a second valve 133.

The first valve 127 is disposed in the refrigerant pipe 111 between the outdoor condenser 113 and the expansion valve 115.

In the present exemplary embodiment, the chiller 29 is connected with an accumulator 123 between the evaporator 117 and the compressor 119, is disposed between the first valve 127 and the accumulator 123, and controls the temperature of a refrigerant by exchanging heat.

The second valve 127 may be a 3-way valve, and accordingly, it passes the refrigerant, which has condensed through the outdoor condenser 113, into the chiller 129, or into the expansion valve 115, not through the chiller 129.

The chiller 129, which is a water-cooled using cooling water as a cooling medium, controls the temperature of a refrigerant by exchanging heat with cooling water with the temperature increased by cooling electric devices.

The accumulator 123 separates a liquid refrigerant in the refrigerant passing through the chiller 129 and in the gaseous refrigerant flowing into the compressor 119 through the evaporator 117, supplies the gaseous refrigerant to the compressor 119, and keeps the liquid refrigerant and then vaporizes and supplies it back to the compressor 119, such that it supplies only a gaseous refrigerant to the compressor 119. Therefore, breakdown and malfunction of the compressor 119 are prevented and efficiency and durability are improved.

In the present exemplary embodiment, the connection pipe 131 is connected to the refrigerant pipe 111 between the expansion valve 115 and the evaporator 117, between the outdoor condenser 113 and the indoor condenser 121 to selectively send some of the refrigerant flowing into the outdoor condenser 113 to the evaporator 117 in the dehumidifying mode.

The refrigerant pipe 111 further has an orifice 125 between the outdoor condenser 113 and the indoor condenser 121 and the connection pipe 133 can be connected with the refrigerant pipe 111 between the orifice 125 and the outdoor condenser 113.

The second valve 133 is disposed in the connection pipe 131.

The second valve 133 may be a check valve for preventing the refrigerant from flowing back into the chiller 129 from the evaporator 117 through the connection pipe 131.

The operation and effect of the dehumidifying mode when the heat pump system 100 for a vehicle which has the configuration described above, according to another exemplary embodiment of the present invention, are described in detail hereafter.

First, in the heating mode for winter in an electric vehicle equipped with the heat pump system 100 having the configuration described above, in accordance with another exemplary embodiment of the present invention, as shown in FIG. 4, cooling water with the temperature increased due to waste heat sources by cooling electric devices flows into the chiller 129 and is then cooled by exchanging heat with external air through a radiator and supplied back to the electric devices, thereby circulating.

In this process, the first valve 127 keeps opening the refrigerant pipe 111 connected with the chiller 129 so that the low-temperature condensed refrigerant from the outdoor condenser 113 is supplied to the chiller 129, and keeps closing the refrigerant pipe 111 connected with the expansion valve 115.

Accordingly, the refrigerant is condensed at lower temperature and low pressure by exchanging heat with the external air through the outdoor condenser 113 and then flows into the chiller 129 through the refrigerant pipe 111 connected with the chiller 129.

The refrigerant flowing in the chiller 129 flows, with the temperature increased by exchanging heat with the cooling water of which the temperature increased, into the compressor 119 through the accumulator 123, and the compressor 119 compresses the refrigerant with the temperature increased into a high-temperature and high-pressure gaseous refrigerant and supplies it to the indoor condenser 121.

The indoor condenser 121 is disposed in an HVAC (Heating, Ventilation and Air Conditioning) module and the external air is increased in temperature through the indoor condenser 121, such that warm external air is supplied to the interior of a vehicle by selective operation of the PTC heater, and thus, heating is made.

Thereafter, the refrigerant, which discharged heat by exchanging heat with the external air flowing into the interior while passing through the indoor condenser 121, changes into a low-temperature and low-pressure refrigerant through the orifice 125, and then it is condensed by exchanging heat with external air through the outdoor condenser 113 and supplied back to the chiller 29. Accordingly, the vehicle is heated by repeating the processes described above.

When there is a need of a dehumidifying mode due to moisture produced on the windows inside the vehicle during the heating mode, the second vale 133 is opened with the heating mode keeping operated.

Accordingly, the refrigerant from the indoor condenser 121 passes through the orifice 125 and some of the refrigerant flowing into the outdoor condenser 113 flows into the evaporator 117 through the connection pipe 131.

Further, the low-temperature and low-pressure refrigerant that has been discharged from the indoor condenser 121 and has passed the orifice 125 flows into the evaporator, such that the external air flowing in the HVAC module decreases in temperature through the evaporator with the refrigerant therein and flows directly to the windows inside the vehicle, and accordingly, it removes the moisture.

Therefore, by using the heat pump systems 1 and 100 for a vehicle according to an exemplary embodiment and another exemplary embodiment of the present invention, which is used in electric vehicles, it is possible to prevent noise and a decrease in durability due to frequent changes between a heating mode and a cooling mode in the related art, and improve the efficiency of the entire system by increasing the travel distance of a vehicle with reduction of the use of a PTC, by performing a heating mode and a dehumidifying mode even without changing into a cooling mode, when interior dehumidification is required during the heating mode in winter.

Further, in the dehumidifying mode, it is possible to reduce the manufacturing cost by decreasing the lengths of the connection pipes 31 and 131 for supplying a refrigerant to the evaporators 17 and 117 to simplify the layout inside a small engine room, such that it is possible to improve spatial usability and reduce a loss of internal pressure by simplifying the package.

Further, since it is possible to prevent unnecessary power consumption by reducing the use of a PTC heater and improving the efficiency of the entire system, it is possible to increase the travel distance with the same amount of power.

For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A heat pump system for an electric vehicle which controls cooling/heating of an interior of the electric vehicle by circulating a refrigerant in accordance a heating mode and a cooling mode, the heat pump system comprising an outdoor condenser that condenses the refrigerant; an expansion valve that is fluidly-connected to the outdoor condenser and expands the refrigerant condensing through the outdoor condenser; an evaporator that is fluidly-connected to the expansion valve and evaporates the refrigerant expanding through the expansion valve; a compressor that is fluidly-connected to the evaporator and compresses the refrigerant evaporating through the evaporator; an indoor condenser that primarily condenses the refrigerant compressed through the compressor, wherein the indoor condenser is connected with the outdoor condenser, the expansion valve, the evaporator, the compressor, and the indoor condenser through refrigerant pipes; a first valve disposed in a first refrigerant pipe of the refrigerant pipes between the outdoor condenser and the expansion valve; a chiller connected with the first valve through a second refrigerant pipe, between the evaporator and the compressor, and controls a temperature of the refrigerant by exchanging heat; a connection pipe selectively allowing some of the refrigerant flowing into the chiller in a dehumidifying mode; and a second valve disposed in the connection pipe.
 2. The system of claim 1, wherein the connection pipe connects the second refrigerant pipe disposed between the first valve and the chiller with a third refrigerant pipe disposed between the expansion valve and the evaporator.
 3. The system of claim 2, wherein the chiller is connected with an accumulator disposed between the evaporator and the compressor, through the third refrigerant pipe, wherein the third refrigerant pipe connects the evaporator, the accumulator, the compressor, and the indoor condenser.
 4. The system of claim 1, wherein the second valve is a check valve that prevents the refrigerant from flowing back into the chiller from the evaporator through the connection pipe.
 5. The system of claim 1, wherein the first valve is a 3-Way valve.
 6. The system of claim 1, wherein a fourth refrigerant pipe of the refrigerant pipes further has an orifice between the outdoor condenser and the indoor condenser, wherein the fourth refrigerant pipe connects the outdoor condenser and the indoor condenser.
 7. The system of claim 1, wherein; in the heating mode, the refrigerant from the outdoor condenser is sent not into the expansion valve and the evaporator, but into the chiller by an operation of the first valve, and is then sent, with the temperature increased, into the compressor, and when the dehumidifying mode is required during the heating mode, some of the refrigerant flowing into the chiller is sent into the evaporator through the connection pipe by opening the second valve, with the heating mode keeping operated.
 8. A heat pump system for an electric vehicle which controls cooling/heating of an interior of the electric vehicle in accordance with a heating mode and a cooling mode, the heat pump system comprising: an outdoor condenser that condenses a refrigerant; an expansion valve that is fluidly connected to the outdoor condenser and expands the refrigerant condensing through the outdoor condenser; an evaporator that is fluidly connected to the expansion valve and evaporates the refrigerant expanding through the expansion valve; a compressor that that is fluidly connected to the evaporator and compresses the refrigerant evaporating through the evaporator; an indoor condenser that primarily condenses the refrigerant compressed through the compressor, wherein the indoor condenser is connected with the outdoor condenser, the expansion valve, the evaporator, the compressor, and the indoor condenser, through refrigerant pipes; a first valve disposed in a first refrigerant pipe of the refrigerant pipes between the outdoor condenser and the expansion valve; a chiller connected with an accumulator between the evaporator and the compressor, disposed between the first valve and the accumulator, and controlling a temperature of the refrigerant by exchanging heat; a connection pipe connected to a second refrigerant pipe of the refrigerant pipes disposed between the expansion valve and the evaporator, to a third refrigerant pipe of the refrigerant pipes disposed between the outdoor condenser and the indoor condenser to selectively send some of the refrigerant flowing into the outdoor condenser to the evaporator in the dehumidifying mode; and a second valve disposed in the connection pipe.
 9. The system of claim 8, wherein the second valve is a check valve that prevents the refrigerant in the connection pipe from flowing back into the chiller from the evaporator.
 10. The system of claim 8, wherein the first valve is a 3-Way valve.
 11. The system of claim 8, wherein the third refrigerant pipe includes an orifice between the outdoor condenser and the indoor condenser and the connection pipe is connected with the third refrigerant pipe between the orifice and the outdoor condenser.
 12. The system of claim 8, wherein; in the heating mode, the refrigerant from the outdoor condenser is sent not into the expansion valve and the evaporator, but into the chiller by an operation of the first valve, and is then sent, with the temperature increased, into the compressor, and when the dehumidifying mode is required during the heating mode, some of the refrigerant flowing into the chiller is sent into the evaporator through the connection pipe by opening the second valve, with the heating mode keeping operated. 